I have an NP2 that I am attempting to upgrade to 4.2.2 update 1. The update seems to go fine but when I use MF Deploy to reset the MAC address I get an error dialog "Unable to erase configuration sector memory". It turns out I was using the MF Deploy that came with .Net MF 4.3. I switched over to MF Deploy from the .Net MF 4.2 install and now I can set the MAC address fine from the Network configuration dialog.
I just wanted to mention that in case anyone else ran into the issue.